Anomalous Monism

Anomalous Monism is a theory about the scientific status of
psychology, the physical status of mental events, and the relation
between these issues developed by Donald Davidson. It claims that
psychology cannot be a science like basic physics, in that it cannot in
principle yield exceptionless laws for predicting or explaining human
thoughts and actions (mental anomalism). It also holds that thoughts
and actions must be physical (monism, or token-identity). Thus,
according to Anomalous Monism, psychology cannot be reduced to physics,
but must nonetheless share a physical ontology.

While neither of these claims, on its own, is novel, their relation,
according to Anomalous Monism, is. It is precisely because
there can be no such strict laws governing mental events that those
events must be identical to physical events. Previous identity
theories of mind had held that claims concerning the identity of
particular mental and physical events (tokens) depended upon the
discovery of lawlike relations between mental and physical properties
(types). Empirical evidence for psychophysical laws was thus held to be
required for particular token-identity claims. Token-identity claims
thus depended upon type-identity. Davidson's position is dramatically
different—it requires no empirical evidence and
depends on there being no lawlike relations between mental and
physical properties. It in effect justifies the token-identity of
mental and physical events through arguing for the impossibility of
type-identities between mental and physical properties. (For
discussion of philosophical positions related to Anomalous Monism, see
the supplement on
Related Views.)

The appeal of Anomalous Monism is due to these enigmatic features, a
fairly straightforward argumentative structure, and its attempt to
bring together an intuitively acceptable metaphysics (monism) with a
sophisticated understanding of the relation between psychological and
physical explanatory schemes (anomalism). Its explicit assumptions are
each intended, on their own, to be acceptable to positions opposing
monism, but, when taken together, to show that monism is in fact
required.

The basic structure of the argument for Anomalous Monism is as
follows. We start with the plausible assumption that some mental
events, such as believing that it is raining, are caused by certain
physical events, in this case the rain. Similarly, it is assumed that
some physical events, such as one's arm rising, are caused by certain
mental events, such as deciding to scratch one's head. Davidson calls
this the Principle of Causal Interaction; we shall call it the
interaction principle:

The Interaction Principle: Some mental events causally
interact with some physical events

Davidson presents this assumption as obvious and not in need of
justification, but we shall see that motivations for it can be found in
parts of his writings (2.2). To this interaction principle is
added the requirement that all singular causal interactions are covered
by strict laws—laws with fully articulated antecedents which
guarantee some fully articulated consequence (for caveats and details,
see 3.1). Davidson calls this the Principle of the Nomological
Character of Causality; we shall call it the cause-law principle:

The Cause-Law Principle: Events related as cause and effect
are covered by strict laws

This cause-law principle was also initially assumed without argument
by Davidson, though we shall see below
(3.2) how he later came to try
to justify it. Now, the assumptions so far seem to point directly to
the existence of strict psychophysical laws—if some particular
mental event m1 is caused by some particular physical event
p1, then, given the cause-law principle, it seems
to follow that there must be a strict law of the form
‘P1 → M1’. That
is, whenever events of kind P1 occur, events of
kind M1 must follow. However, Davidson then claims
that there can be no such laws. He calls this the Principle of the
Anomalism of the Mental, and it holds that mental properties are not
suitable for inclusion in strict laws of any kind; we shall call it
the anomalism principle:

The Anomalism Principle: There are no strict laws on the
basis of which mental events can predict, explain, or be predicted or
explained by other events

Davidson offered loose ruminations concerning rationality and
rationalizing explanations, which purportedly constitute the very
nature of mental properties, in support of the anomalism principle
(4.2). All of this will be discussed in detail below.

With the interaction principle, the cause-law principle, and the
anomalism principle now in place, we can see that there is a tension in
need of resolution. From the interaction and cause-law principles it
follows that there must be strict laws covering the interaction between
mental and physical events. But the anomalism principle entails that
there are no strict psychophysical laws. How can all three principles
be held simultaneously?

To resolve the tension, Davidson noted that while the cause-law
principle requires that there be strict covering laws, it doesn't
specify the vocabulary in which those laws must be formulated. If
particular physical event p1 causes particular mental event
m1, and there must be some strict law covering
this interaction, but there is no strict law of the form
‘P1 → M1’,
then there must be some other law,
‘?1 → ?2’, which
covers the causal relation between p1
and m1. That is, m1
and p1 must instantiate properties suitable for
inclusion in strict laws; but since we know that
M1 is not a property of this
kind, m1 must instantiate some other
property. Davidson's ingenious deduction at this point was that this
property must be physical, since only the physical sciences hold out
the promise of a closed system of strict laws (Davidson 1970,
223–24; on the notion of a closed system,
see 5.1 and the supplement on
Causal Closure of the Physical in the Argument for Monism).
Therefore, every causally interacting mental event must
be token-identical to some physical event—hence, monism
(5.1):

Monism: Every causally interacting mental event is
token-identical to some physical event

In arguing in this way, Davidson relies upon a key distinction between
explanation and causation. While explanation is, intuitively, an
intensional notion—one sensitive to how events are
described—causation is extensional, obtaining between pairs of
events independently of how they are described. For example, a
bridge's collapse is explained by the explosion of a bomb. That
explosion, let us suppose, was the most newsworthy event of the
day. While the most newsworthy event of the day caused the
bridge's collapse, ‘the most newsworthy event of the day’
does not
explain that collapse. Telling someone that it was the most
newsworthy event of the day that explained the bridge's collapse
wouldn't provide an explanation—it wouldn't make the bridge's
collapse intelligible to the audience—though it would pick out
its actual cause. How the cause is described is relevant to whether an
explanation occurs. Causes and effects can be accurately picked out
using a variety of expressions, many of which are not explanatory. As
we shall see, the distinction between causation and explanation is
crucial to Anomalous Monism (6.1–6.3).

Finally, to alleviate certain concerns about the adequacy of the
form of physicalism he was endorsing, Davidson endorsed a dependency
relation of supervenience of the mental on the physical, and claimed
that it was consistent with Anomalous Monism (5.1,
5.3) (Davidson 1970,
214; 1993; 1995a, 266):

Supervenience of the Mental on the Physical: if two events
share all of their physical properties, they will share all of their
mental properties

In what follows (2–5), each step of this argument will be analyzed
and discussed separately, but always with an eye to the overall
argument. In 6, a central objection to Anomalous Monism—that it
appears unable to account for the causal/explanatory power of mental
events and properties—will be explained and discussed. (For
discussion of the relationship between Anomalous Monism and two other
pillars of Davidson's philosophy—his rejection of conceptual
relativism and commitment to semantic externalism—see the supplement on
Related Issues.)

The interaction principle states that some mental events causally
interact with some physical events. In this section we will look
briefly at a number of issues related to this principle: how mental
and physical events are demarcated, the nature of events themselves,
the scope of the interaction principle, the relationship between
mental events and causation, and the use of the interaction principle
in establishing one component of mental
anomalism—psychological anomalism, according to which
there can be no strict, purely psychological laws. Psychological
anomalism is to be distinguished from psychophysical
anomalism, which holds that there can be no strict psychophysical
laws. This latter thesis will be explored in detail in our discussion
of the anomalism principle (4).

Davidson restricts the class of mental events with which Anomalous
Monism is concerned to that of the propositional
attitudes—states and events with psychological verbs such as
‘believes’, ‘desires’, ‘intends’
and others that subtend ‘that-’ clauses, which relate
subjects to propositional contents such as ‘it is raining
outside’. Anomalous Monism thus does not address the status of
mental events such as pains, tickles and the
like—‘conscious’ or sentient mental events. It is
concerned exclusively with sapient mental events—thoughts with
propositional content that appear to lack any distinctive
‘feel’.

Though traditional and intuitive, this way of dividing up the domain
of the mental isn't without controversy. Generally,
Davidson expresses some skepticism about the possibility of formulating
a clear and general definition of the class of mental phenomena
(Davidson 1970, 211). And he is suspicious about the idea of mental
states given to, but uninterpreted by, concepts (Davidson 1974a), which
is how philosophers have often thought of conscious phenomena. But for
current purposes the class of propositional attitudes will suffice as a
criterion for the mental. One key reason for so limiting the reach of
Anomalous Monism, as we shall see (4.2), is that it is the
rational status of the relevant mental events that Davidson
usually cites as responsible for mental anomalism. Conscious events
have traditionally been thought to occur in non-rational animals, a
position with which Davidson shows some sympathy (Davidson 1985a). Such
events thus appear to fall outside of the domain of the rational, and
thus outside of the purview of Davidson's argument.

Davidson is even less helpful about offering a criterion for the
‘physical’ (Davidson 1970, 211). One half-hearted attempt
comes in the statement that

[p]hysical theory promises to
provide a comprehensive closed system guaranteed to yield a
standardized, unique description of every physical event couched in a
vocabulary amenable to law. (Davidson 1970, 224)

This is at best a promissory note about some future language of
‘physics’—the ‘true’ physics—and
it incorporates a requirement of the causal closure of the physical
domain that creates problems for certain aspects of Anomalous Monism
(see the supplement on
Causal Closure of the Physical in the Argument for Anomalous Monism).
It is probably best to take a ‘physical’
description simply to be one that occurs in the language of a future
science that is similar to what we call ‘physics’ today but
with none of its inadequacies. One important component of such
descriptions is their capacity to figure in strict laws of nature
(see 3.1). While this is non-negotiable for physical terms, it is an open
question for mental terms, and Davidson will be arguing (4) for a
negative answer.

When Davidson first argued for Anomalous Monism he subscribed to a
causal criterion of event-individuation, according to which two events
(event-descriptions) are identical (co-refer) if they share all the
same causes and effects (Davidson 1969). He much later came to reject
that criterion in favor of one according to which events are identical
if and only if they occupy the same spatiotemporal region (Davidson
1985b). The difference between these views will not, however, be
reflected in our discussion. It does not appear to affect either the
derivation or the essential nature of Anomalous Monism. For our
purposes, Davidson's central claims are that what makes an event mental
(or physical) is that it has a mental (or physical) description, and
the extensionalist thesis that events are concrete entities that can be
described in many different ways (‘the flipping of the light
switch’, ‘the illuminating of the room’ and
‘the alerting of the burglar that someone is home’ can all
pick out the same one event in different terms). (For controversies
concerning extensionalism, see 5.2 and the
supplement on Related Issues
(Anomalous Monism and Scheme-Content Dualism).)

The interaction principle states that at least some mental events
cause and are caused by physical events (Davidson 1970, 208). This
leaves open the possibility of mental events that do not causally
interact with physical events. However, given Davidson's early views
about event-individuation (the causal criterion) it is unclear that
this possibility can be realized. His later views on
event-individuation appear to leave this possibility open, but his
general claims about the causal individuation of mental contents and
attitudes (see
4.3 and 6.3 below)
also stand in some tension with this
possibility. In any case, Davidson goes on to say that he in fact
believes that all mental events causally interact with physical events
(Davidson 1970, 208), but he restricts his argument only to those that
actually do. Given the pressures just noted in favor of the inclusive
reading of the interaction principle, we shall assume it in what
follows.

The interaction claim itself should be understood as follows: some
events that have a mental description or instantiate a mental property
cause and are caused by events that have a physical description or
instantiate a physical property. Formulating the interaction principle
in this way both clears the way for an extensional reading of the
causal relation (events are causally related no matter how they are
described), and also leaves open the possibility, which Davidson will
subsequently argue for, that mental events in particular must have some
non-mental description/instantiate some non-mental property. At this
stage that possibility is left as an open question, but it is important
to notice that for it to be an open question we need to at least allow
for a distinction between events and the ways in which they are picked
out in language.

Though this will be focused on separately below (6), it is also
important to recognize that we are beginning with the assumption that
mental events cause and are caused by physical events. Many critics of
Anomalous Monism have claimed that it is difficult to see how the
position avoids epiphenomenalism—the view that mental events
are causally/explanatorily impotent—and that Anomalous Monism
is therefore unacceptable as an account of the place of the mental in
the physical world. However, since Anomalous Monism is based
upon the interaction principle, Davidson can claim in response
that if Anomalous Monism is true, then mental events are already known
to have a kind of causal efficacy. As we shall see, this point is not
by itself sufficient to ward off all epiphenomenalist concerns about
Anomalous Monism. But it does serve to remind us of the full framework
within which challenges to Anomalous Monism must be assessed, and in
particular brings out the reliance of that framework on specific
assumptions about causality (see Sections
4.3,
6, and Yalowitz 1998a).

What needs to be noted at this point is that Davidson argued early
on for the claim that mental events have causal efficacy, through
noting a problem for non-causal accounts of action explanation
(Davidson 1963). Mental events and states explain action by making it
intelligible—rational—in light of the agent's beliefs
and purposes. The challenge that Davidson raised for non-causal
theories of action explanation was to account for the fact that, for
any action performed, there may well be a large number of mental events
and states true of the agent, and capable of rationalizing the action,
but that don't thereby explain that action. The agent acted
because of some specific beliefs and purposes, but other
beliefs and purposes of his could just as easily rationalize that
action, and thus be cited in its explanation. Was the agent moving his
hand as he did because he wanted to swat the fly, relieve a cramp, or
wave in greeting? He may well have wanted to achieve all three of these
aims, but still only in fact performed the action because of
one of these reasons. How do we understand ‘because’ so as
to rule out the pretenders? Davidson's claim was that it is only if we
understand ‘because’ as ‘was caused by’ that we
can justifiably pick out the genuine explanans—thereby
imputing causal potency to mental events.

What exactly does this argument show? It is intended to tell
against non-causal theories of action, which deny that reasons explain
actions by causing them. There have been sophisticated attempts, on the
behalf of non-causal theories of action explanation, to respond to this
challenge (von Wright 1971; Wilson 1985; Ginet 1995; for a good
overview, see Stoutland 1976; and see related discussion in
6.3.)
However, assuming the argument is successful, while it does establish
mental efficacy of a kind, it does not by itself establish the
interaction principle. Establishing that reasons explain actions by
causing them, and that therefore reasons causally interact with
actions, does not establish that reasons causally interact
with physical events. Dualists who reject the identity of
mental and physical events will surely object.

A key point to grasp in many of the issues raised by Anomalous
Monism is that there is an important distinction between action and
behavior. According to Davidson, action is intentionally
described behavior—the moving of a hand through space in
a certain way may, but need not, be an action of waving or swatting or
any action at all. It may simply be mere bodily behavior—as
happens as the result of a muscle twitch or a strong gust of wind. The
behavior must be caused by an agent's beliefs and desires in order to
be action. However, while this is necessary for action, it is not,
according to Davidson, sufficient. The behavior must be caused in
the right way by the beliefs and desires. Davidson notes the
possibility of cases where an agent's beliefs and desires cause
behavior which is not rationalized by those states, and thus not
action. A mountain climber might become so unnerved by his desire to
rid himself of an annoying second climber sharing his rope and belief that
jiggling the rope is a means for doing so that he unintentionally
jiggles the rope, leading to the loss of the second climber. This is
not an action—it is mere behavior that happens to him, no
different than if caused by a muscle twitch or gust of wind. It is
caused in the wrong way—a “deviant causal
chain”—by the belief and desire, and so is not an action.
Davidson is skeptical about the possibility of cashing out what it
means to be caused in the right way (Davidson 1973b, 78–9),
for reasons relating to mental anomalism (Davidson 1973b, 80; see
4 for
explicit discussion). The key point for now is that because Davidson
rejects the possibility of analyzing action in terms of behavior caused
in a particular way by reasons, the point made by the
‘because’ argument cannot be used to establish that mental
events cause physical events. It does not follow from the fact that
reasons must cause actions in order to explain them that
reasons must cause behavior or (the interaction principle)
that reasons do cause behavior. It does not entail that
actions are physical behavior.

This point is important when one considers the wider framework to
which the interaction principle contributes. Since Davidson is
attempting to derive monism from it and other principles that are
themselves neutral about the metaphysics of mind, he cannot assume that
action is (identical with) behavior on pain of circularity. Once monism
has been established, Davidson will be in a position to deploy the
‘because’ point in order to argue for the claim that mental
events are causally efficacious with respect to physical events. How
this relates to the wave of epiphenomenalist criticism about Anomalous
Monism will be explored in detail below (6, and see the
supplement on
Mental Properties and Causal Relevance).
To summarize, the
interaction principle is an unargued assumption in the Davidsonian
framework, one that does not assume monism, and the
‘because’ argument, while important for ruling out
non-causal theories of action, does not itself establish the
interaction principle.

Davidson uses the interaction principle to establish directly one
part of mental anomalism—psychological anomalism,
which denies the possibility of strict, purely psychological laws of
the form
‘M1 & M2 → M3’
(Davidson 1970, 224; 1974b, 243).
For if physical events causally impact on mental events, then the
mental domain is ‘open’, and any laws in which mental
predicates figure will have to take this into account (for related
discussion, see the supplement on
Causal Closure of the Physical in the Argument for Anomalous Monism).
More generally, physical conditions will always play some role in any
plausible psychological generalizations, because physical intervention
(e.g., injury) is always a possibility and can prevent the occurrence
of the consequent ‘M3’. Thus, the
only potentially true and strict laws in which psychological
predicates can figure are variants of the psychophysical form
‘P1 & M1 & M2 → M3’.
Psychophysical anomalism, the other component of mental
anomalism and the one that denies the possibility of such strict laws,
is thus the view that Davidson focuses on establishing.

The cause-law principle states that events related as cause and
effect are covered by strict laws. In the earliest formulations of
Anomalous Monism, Davidson assumed but did not argue for this
principle. His later argument in support of it will be considered
below (3.2), along with objections to the principle
(3.3). But we need
to consider the nature of the requirement contained in this claim, and
how it relates to the framework out of which Anomalous Monism is
deduced.

The nature of the strict laws required by the cause-law principle is
as follows. For any causal relationship between particular events
e1 and e2, there must be a law
of the form
‘(C1 & D1) → D2’,
where ‘C1’ states a set of standing
conditions, and ‘D1’ is a description
of e1 that is sufficient,
given C1, for the occurrence of an event of the
kind ‘D2’, which is a description
of e2. Traditionally, a strict law has been
thought of as one where the condition and event-types specified in the
antecedent are such as to guarantee that the condition or
event-types specified in the consequent occur—the latter
must occur if the former in fact obtain. But indeterministic
or probabilistic versions of strict laws are possible as well (Davidson
1970, 219). The point that distinguishes strict laws is not so much the
guaranteeing of the effect by satisfaction of the antecedent as the
inclusion, in the antecedent, of all conditions and events that can be
stated that could possibly prevent the occurrence of the
effect. A strict indeterministic law would be one that
specified everything required in order for some effect to occur. If the
effect does not occur when those conditions obtain, there is nothing
else that could be cited in explanation of this failure (other than the
brute fact of an indeterministic universe). For reasons of simplicity,
we will assume determinism in this discussion, though what is said
about strict laws could be carried over without remainder to strict
indeterministic laws.

The cause-law principle is aimed, in the first instance, at laws of
succession, which cover singular causal relationships between
events at distinct times. However, as will become clearer below,
mental anomalism also takes in bridge laws that would
correlate simultaneous instantiations of mental and physical
predicates as well—such as
‘P1 → M1’,
‘M1 → P1’,
or
‘P1 ↔ M1’. Indeed,
mental anomalism rejects the possibility of any strict law in
which mental predicates figure (where those predicates figure
essentially, and are not redundant)—including (as we have seen
(2.3)) laws formulated with purely mental
predicates
(‘(M1 & M2) → M3’),
as well as laws with mental predicates in either the antecedent or
consequent, such as
‘(M1 & M2) → P1’
and
‘(P1 & P2) → M1’
and mixed variants of these (see 4).

The denial of strict laws of these forms is consistent with allowing
hedged versions of them which are qualified by a ceteris
paribus clause. ‘All things being equal’ or
‘under normal conditions’, such psychological and
psychophysical generalizations can, according to Davidson, be
justifiably asserted (Davidson 1993, 9). As will be discussed below
(4), denying the strict version of these generalizations amounts to
denying that the qualifying clause ‘ceteris
paribus’ can be fully explicated. That is,
‘ceteris paribus, ((M1 &
M2) → P1)’ cannot be transformed into
something like ‘(P2 & P3 &
M1 & M2 & M3) →
P1’ (for a related discussion of this particular
issue, see the debate between Schiffer 1991 and Fodor 1991).

(Davidson organizes his discussion of this transformation process,
and Anomalous Monism more generally, around a distinction between
‘homonomic’ and ‘heteronomic’ generalizations
(Davidson 1970, 219). That distinction is extremely problematic
for the purposes of establishing Anomalous Monism, and is set aside
here in favor of the related (but by no means identical) distinction
between strict and ceteris paribus generalizations. For
discussion of the former distinction, see the supplement on
Homonomic and Heteronomic Generalizations.)

Davidson argues for the cause-law principle—that singular causal
relations require strict covering laws—on the basis of a conceptual
interconnection between the concepts of physical object,
event and law. As he says, “our concept of a
physical object is the concept of an object whose changes are governed
by laws” (Davidson 1995a, 274). The interconnections are
established partly in response to C.J. Ducasse's attempt, in reaction
to Hume's regularity theory of causation, to define singular causal
relations without appeal to covering laws (Ducasse 1926).

Simply put, Ducasse defined some particular event c as the cause of
some effect e if and only if c was the only change occurring in the
immediate environment of e just prior to e. The striking of the match
is the cause of the flaming match just insofar as the striking is the
only change occurring in the immediate vicinity of the flaming match
just prior to the flaming of the match. Ducasse intended this
definition to rebut Hume's claim that singular causal relations between
particular events must be analyzed in terms of regularities between
types of events (and thus laws). Indeed, Ducasse claimed that Hume was
wrong to deny that we have the ability to perceive singular causal
relations—this denial being the basis for Hume's subsequent
regularity account (see 3.3).
For, according to Ducasse, we can
perceive that some event is the only change in the immediate
environment of some subsequent event just prior to that event's
occurrence. (We can, of course, be wrong in thinking that this is what
we have in fact perceived. But as Ducasse points out, the same problem
plagues Hume's own account—we can be wrong that what we have
perceived are instances of types which bear a regular relation to each
other. But this does not lead Hume to hold that since we can't
infallibly perceive that some succession is an instance of a
regularity, we cannot form the concept of causality in terms of
regularity. The same thus applies to Ducasse's own account.)

Davidson notes the heavy dependence, in Ducasse's account, on the
notion of a ‘change’. And he asks whether we really have a
purchase on this concept absent appeal to laws. There are two aspects
of this concern. First, the notion of ‘change’ is short for
‘change of predicate’—a change occurs when a
predicate true of some object (or not true of that object) ceases to be
true (or comes to be true) of that object. And this leads directly to
questions about how predicates are individuated and their relationship
to laws (see below). Second, and at a more general level, the notion of
‘change’ has itself changed over time—for instance,
Newtonian mechanics defines a change differently than Aristotelian
physics, so that continuous motion counts as a change, and thus
requires an explanation, according to the latter but not the former.
Thus, the very notion of ‘change’ is theory dependent, and
therefore (Davidson holds) presupposes the notion of ‘law’,
in the sense that something counts as a change, and thus as having a
cause, only against a background of theoretical principles.

This second point does not appear to deliver the result Davidson is
after—establishing that each causal interaction must be covered
by a particular strict law. The claim that
something is a change, and thus has a cause, only if certain
theoretical assumptions are in place is consistent with the claim
that those assumptions (for
instance, that uniform rectilinear motion does not count as a change)
cannot play the explanatory role for specific causal interactions that
strict laws are supposed to play. They are simply of too general a
nature—they don't enable predictions or explanations of any
particular events. And in any case, there appears to be nothing in
Davidson's considerations here that forces the requirement that the
covering laws be strict as opposed to irreducibly ceteris
paribus. (As we have already seen (3.1),
Davidson himself has insisted upon the legitimacy and ubiquity of
such laws in scientific explanation.)

Returning to the first point about predicate-individuation, Davidson
claims that “it is just the predicates which are projectible,
the predicates that enter into valid inductions, that determine what
counts as a change” (Davidson 1995a, 272). We know from Nelson
Goodman's ‘new riddle of induction’ (Goodman 1983) that we
can invent predicates, such as ‘grue’ and
‘bleen’ (where an object is grue if it is green and
examined before 2020 or otherwise blue, and an object is bleen if it
is blue and examined before 2020 or otherwise green) so that a green
object goes from being grue to bleen over the course of time without
having changed in any intuitive sense. It will continue to be green,
though it will also be true that it ceases to be grue and comes to be
bleen. Contrary to much discussion of Goodman's riddle, Davidson holds
that such unusual predicates can be projectible, and figure in laws,
but only when appropriately paired with other such predicates (
“All emeralds are grue” is not lawlike, but “All
emerires are grue” is (where “emerire” is true of
emeralds examined before 2020 or otherwise sapphires ). What is
crucial for Davidson is that to understand the notion of change, which
is so closely tied to the notion of causation, one must understand the
notion of a projectible predicate—one appropriate for use in
science—and this notion inevitably brings in the notion of
law. Changes are described by predicates suitable for inclusion within
laws. But how does this relate to the cause-law principle? Once again,
it is unclear why Davidson would think that it is the notion of
a strict law in particular that this line of argument
motivates.

A related line of argument that Davidson offers
(see 4.3) appears to suggest that
dispositional predicates—those defined in terms of the effects
they tend to bring about—are not suitable for inclusion in
strict laws (generalizations in which they figure are always qualified
by a ceteris paribus clause), but there must be strict laws
at the bottom, so to speak, of the dispositional
vocabulary. Davidson's discussion of this issue refers back to an
older debate about the status of dispositional
terms—specifically, whether they are ‘place-holders’
for predicates that are non-dispositional (‘intrinsic’ or
‘manifest’) (see Goodman 1983, 41ff). Whatever one's view
about that issue, it again does not appear that Davidson has provided
adequate argument for establishing that strict laws (as
opposed to ceteris paribus laws) are required for our
dispositional vocabulary to operate as it does. So Davidson does not
appear to have provided the cause-law principle with a plausible
rationale (for skepticism about the principle, see Anscombe 1971,
Cartwright 1983, McDowell 1985, Hornsby 1985 and 1993,
and 3.3 below). This is not to say that it
is false, or even that it is implausible to assume it in his argument
for Anomalous Monism. Many find the principle highly intuitive, and it
is worthwhile to explore its relation to the other central claims in
Davidson's framework.

The cause-law principle has come in for a lot of criticism since it
received its canonical formulation in Hume's regularity theory of
causation, and it is worth briefly reviewing some of the central
objections relevant to Davidson's own discussions. This will make
clear how important it is, for an argument such as Davidson's for
Anomalous Monism, that some justification for the thesis ultimately be
provided.

An initial objection is that Hume's analysis of singular causal
statements (‘a caused b’ is true if and
only if ‘whenever an A occurs, it is followed by an
occurrence of a B’), which articulates his own version
of the cause-law principle, is not an accurate rendering of the way in
which we typically use the term ‘cause’. We are confident
in judgments such as ‘Harry's smoking caused his lung
cancer’ while knowing that in fact not all smokers are stricken
by lung cancer. This point is entirely general—we make singular
causal judgments all the time without believing in (indeed, while
knowing the falsity of) the associated universal generalization (see
Anscombe 1971). However, Davidson's extensionalism about causality
provides a straightforward response to this concern. His view is that
while we may not believe in the associated universal generalization,
that is consistent with there being some universal
generalization, stated in a different vocabulary than the singular
causal statement, which ‘covers’ that statement. (It is
worth noting that Davidson rejects Hume's analysis of singular
causal statements in terms of universal generalizations—he
holds that the requirement of such a covering generalization is
necessary but not sufficient for the truth of such a statement
(Davidson 1967).)

While this response does appear to meet the objection, it raises the
following concern, which is behind a related objection to the cause-law
principle: no one in fact seems to know any true predictive
‘strict’ laws (in the literal sense of that term). Now,
while it is certainly consistent with this point that there are or even
must be such laws, it becomes more pressing to know why we should think
this if we cannot even offer any examples. It is well and good for
Davidson to point to the possibility of strict covering laws that
transcend our current knowledge, but we need to know why we should
believe in such things. Science seems to have done well for itself
without any apparent use of them.

Another objection to the cause-law principle comes from the state of
contemporary physics. According to quantum mechanics, it is not simply
difficult or impossible for us to state such laws for quantum
phenomena. Rather, quantum theory appears to entail that determinism
fails to obtain at the level of microparticles. What the theory and the
behavior of such particles tells us is that causation, at least at the
level of micro phenomena, is indeterministic. And this indeterminism is
claimed to be inconsistent with the requirement of strict laws. This
objection to the cause-law principle, then, is that philosophy should
never dictate to science on empirical matters. Observation of the world
tells us that strict laws are impossible in this domain even while
causation is present, in direct contradiction of the cause-law
principle.

Now, we have already seen Davidson's own response to this sort of
objection (3.1). As traditionally construed,
strict laws are supposed to guarantee the consequent condition on the
basis of the antecedent condition. But they do not need to provide
such a guarantee. What strict laws require is that the antecedent
include all conditions and events that could possibly prevent the
occurrence of the consequent. If the consequent does not occur when
all these conditions have been accounted for, there is nothing else to
be cited in explanation of the non-occurrence other than the sheer
brute fact of an indeterministic universe. So indeterministic
causation is entirely consistent with the cause-law principle
(Davidson 1970, 219). The determinist/indeterminist and
strict/nonstrict law distinctions do not map neatly onto each
other. An indeterministic law can be universal, exceptionless and
true. This point does not appear to be recognized by central
proponents of the indeterministic objection to strict laws (see
Cartwright 1983).

A final objection to the cause-law principle which is more internal
to the wider framework of Anomalous Monism has been put forth in
McDowell 1985. McDowell sees a tension between Davidson's allegiance to
the cause-law principle and his rejection of ‘the dualism of
scheme and content’ (Davidson 1974a). Briefly, the dualism
Davidson opposes is the idea that, for instance, a perceptual judgment
is the rational upshot of an interaction between a concept and an
nonconceptualized experiential element—the sensory input. Given
Davidson's systematic rejection of this idea, McDowell believes he
ought to disavow the cause-law principle. McDowell doesn't think the
principle is required for a minimal version of materialism (see
the supplement on
Related Views (Bare Materialism),
and without the
need to justify materialism McDowell sees the principle as lacking any
motivation in Davidson's framework. For discussion of this issue and
others related to scheme-content dualism and Anomalous Monism, see the
supplement on
Related Issues
(Anomalous Monism and Scheme-Content Dualism).

The anomalism principle states that there are no strict laws on the
basis of which mental events can predict, explain, or be predicted or
explained by other events. In this section we look at different
interpretations of the argument for this principle. Davidson's own
formulations, while suggestive, are notoriously vague and often appeal
to very different sorts of considerations, including aspects of
language and interpretation, questions about psychological explanation,
and the nature of causality and dispositions. We shall be looking at
specific interpretations as well as the problems they face in providing
a compelling rationale for both the anomalism principle and Anomalous
Monism.

While differing in important ways, the various formulations of the
argument, as well as the objections to them, exhibit a discernible
pattern: proponents of mental anomalism highlight some feature of
mental properties that is claimed to (1) sharply individuate them from
physical properties and (2) create a conceptual tension with physical
properties that precludes the possibility of strict lawful relations
between these properties. According to the objections, however, the
highlighted feature of mental properties either does not serve to
distinguish it from physical properties or does not actually stand in
any conceptual tension with physical properties that rules out lawlike
relations. We will consider each interpretation, and its problems, in
turn. In a later section (5.3) we will
look at another objection related to the anomalism
principle—that it is inconsistent with Davidson's invocation of
the doctrine that mental properties stand in a relation of
supervenience to physical properties. For discussion of the relation
between the anomalism principle and Davidson's views about
scheme-content dualism and semantic externalism, see the supplement on
Related Issues.

Mental anomalism, as initially formulated by Davidson, holds that
there can be no strict laws on the basis of which mental events can be
predicted and explained (Davidson 1970, 208). It is thus restricted to
ruling out strict laws of succession with mental predicates occurring
in the consequent—laws such as
‘P1 → M1’,
‘(M1 & P1) → M2’, or
‘M1 → M2’.
It thus denies that the occurrence of
particular mental events such as coming to believe or intend
something, or intentionally acting in some way, can be explained by
appeal to strict covering laws. But as becomes clear, Davidson's
considered position rejects the possibility of any strict
laws in which mental predicates figure—and this includes, in
particular, bridge laws of the form
‘P1 ↔ M1’,
which form the basis of type-identity theories of mind, as well as any
strict laws with mental antecedents. We have already seen how strict
purely psychological laws are ruled out by the interaction principle
(2.3). And, at a more general level, it rules
out purported solutions to the problem of deviant causal chains noted
in 2.2, which would spell out, in terms of some
required physical and also, perhaps, mental conditions, how behavior
must be caused by reasons (“caused in the right way”) in
order to be action. (That some physical conditions are necessary in
such an analysis is guaranteed, as we have seen
(2.3), by the open nature of the mental and
subsequent psychological anomalism.) Any such adequate analysis of
action would entail particular psychophysical laws of the form
‘(M1 & M2 & M3 & P1) → P2’. For
such an analysis would state that whatever behavior
(P2) which in fact is caused in the right way
(M3 & P1) by
reasons
(M1 & M2)
would be the action that is rationalized by those
reasons. This provides a schema for generating strict psychophysical
laws: by plugging in particular reasons and the causal
conditions P1 and M3 proffered
by the analysis, we get a strict predictive psychophysical law simply
by noting what effect is produced by these causes. (In the course of
an extended discussion of the problem of deviant causal chains, Bishop
1989, 125–75, fails to see this connection between it and mental
anomalism—see 164.) With strict purely psychological laws thus
already ruled out, the focus now is on strict psychophysical laws.

It is useful to view Davidson's attack against psychophysical laws in
light of an argument, in vogue in the 1950s and 1960s, against the
claim that reasons are causes of the actions they explain. This
argument was referred to as the “Logical Connection
Argument” (see Stoutland 1970). According to this argument,
reasons cannot be held to explain actions by causing them because (1)
causes and effects must be logically distinct from each other (one of
Hume's requirements on causality) but (2) reasons and the actions they
explain bear a quasi-logical connection to each other, by virtue of
the rationalizing relation between them. That relationship is
quasi-logical because not just any reason can explain any
action—only those reasons which actually rationalize (make
intelligible) an action can explain it. Davidson's own influential
response to this argument was to distinguish between causal relations,
which obtain between events no matter how they are described, and
logical relations, which obtain between particular descriptions of
events. The Logical Connection Argument fails to recognize this simple
distinction. The distinction allowed Davidson to merge two key ideas
in his theory of action—that reasons explain by causing, and
that they explain by rationalizing (Davidson 1963, 13–17). As we
shall see below, however, Davidson appears to accept a basic
distinction at the heart of the Logical Connection Argument—that
the rationalizing relationship bears a certain key property
(quasi-logical status) that is at odds with the relationship between
physically described, causally related events.

Davidson's explicit considerations in favor of mental anomalism
appeal to factors about the interpretation of action (linguistic as
well as non-linguistic) and the ascription of mental states and events
to persons. Several distinguishable features are noted—holism
with respect to particular ascriptions, indeterminacy with respect to
systematic interpretative frameworks, and the responsiveness of mental
ascription to an ideal of rationality. According to holism, particular
mental states can be cited in explanation of behavior only in the
context of other mental states, which in turn depend upon others.
Davidson claims that this dependency and holistic interrelatedness is
“without limit” (Davidson 1970, 217). This echoes a related
point he makes about the impossibility of definitional reduction of
mental states in purely behavioristic terms, because of the
ineliminable need for mental caveats (e.g., that the person understands,
or notices or cares….) qualifying any attempt to state
non-mental conditions for mental states.

Davidson presents these claims about definitional reduction as facts
which “provide at best hints of why we should not expect
nomological connections between the mental the physical”
(Davidson 1970, 217). If definitional reduction of this kind were in
fact impossible, it would rule out the possibility of a subclass of
strict psychophysical laws—those relating mental states with
non-intentionally described behavior—but the basis for this
impossibility would not have been explained. In fact, however, without
knowing what that basis is supposed to be, we have no reason to accept
Davidson's claim that definitional reduction is indeed impossible. What
prevents us from articulating all the required caveats? Without a
rationale in hand, nothing prevents a reductionist from simply offering
us detailed definitions and challenging us to come up with
counterexamples. Something both principled and convincing is clearly
needed. Davidson's concerns about definitional reduction are
‘hints’ concerning nomological reduction only in the sense
that they draw out our intuitions about something standing in the way
of formulating such laws. What that obstacle is needs clear
formulation.

At times, Davidson appeared to flirt with the idea that the missing
link was provided by the thesis of the indeterminacy of translation,
developed by W.V Quine (1960) and endorsed by Davidson (1970, 222;
1979). This thesis claims that there are empirically adequate but
non-equivalent complete frameworks for assigning linguistic meanings
and mental states to a person on the basis of his behavior, and that
there is no fact of the matter that determines that one but not other
such frameworks is correct. In particular, there are no physical
facts, inside a person's body or head or outside in the external
world, that could settle whether a person's words refer to some
determinate range of objects rather than some other range, or whether
one rather than another systematically interdependent set of mental
states, with distinct distributions of truth values, is true of that
person (see Davidson 1979). If the indeterminacy thesis is true, then
on the face of it there would be some rationale for rejecting the
possibility of psychophysical laws. For if all physical facts are
consistent with different psychological/semantic assignments, then it
seems that knowing all the physical facts could not tell us whether
some mental states were true of some person, or some meaning true of
her words—neither could be exceptionlessly predicted or
explained, just as mental anomalism maintains.

There are two problems with this, however. First, this would do
nothing to rule out certain psychophysical laws, such as those of the
form
‘M1 → P1’. And
so it couldn't ground the completely general thesis of mental
anomalism. But more importantly, Davidson himself holds that the least
controversial versions of indeterminacy, having to do with diverging
reference schemes, amount to mere notational variance—as he puts
it, meaning is what is invariant between empirically adequate
translation schemes (Davidson 1977, 225; 1999a, 81). And given that
such schemes are generated through a purely mechanical permutation
function (Davidson 1979, 229–30) it is a relatively simple
technical trick to take these different schemes into account when
formulating psychophysical laws. The laws, for instance, could be
formulated with disjunctive predicates
(‘P1 → (M1 ∨ M2 ∨ M3’).
Or, if such predicates are considered problematic, the laws could be
of the form
‘P1 → M*’,
where ‘M*’ picks out the invariant element
between the empirically equivalent theories. So it is not at all clear
that indeterminacy in and of itself is capable of supporting an
across-the-board rejection of strict psychological or psychophysical
laws. And Davidson ultimately acknowledges this, in stating that
anomalism would hold even if indeterminacy didn't (Davidson 1970,
222).

What is responsible for the possibility of indeterminacy, however,
is the role of the principle of charity in formulating a theory of
another person's behavior (Davidson 1970, 222–23). And this principle
is closely aligned for Davidson with mental anomalism. According to
this principle, we must “try for a theory that finds him
consistent, a believer of truths, and a lover of the good (all by our
own lights, it goes without saying)” (Davidson 1970, 222). In the
process of coming to understand another, by ascribing mental states and
events to him and meanings to his words, we must, Davidson claims,
stand ready to adjust previous assignments of meanings and mental
states and events based upon new evidence about the person and how it
relates to the overall project of finding him and his behavior
intelligible. There are two key points here that for Davidson suggest
mental anomalism. First, we never have all possible evidence—we
must maintain an openness to better interpretations of previous
behavior as new evidence becomes available. Interpretation is always
ongoing. And second, ‘better’ interpretations are those
made in light of the constitutive ideal of rationality.
Consequently, Davidson claims,

there cannot be tight
connections between the realms [of the mental and the physical] if each
is to retain allegiance to its proper source of evidence.
(Davidson 1970, 222)

Rationality is claimed by Davidson to be constitutive of the
mental in the sense that something only counts as being a
mind—and thus an appropriate object of psychological
attributions—if it meets up to certain rational standards. This
constitutive idea is open to weaker and stronger interpretations. The
weaker interpretation sees only very basic logical, semantic or
conceptual constraints on understanding others—and thus what is
constitutive of minds—which allows for significant variation
as one moves further out from these to more substantive principles of
practical reasoning and theoretical reasoning, and even more when
extending out further to desires and values. The stronger
interpretation appears to be suggested in the quote from Davidson
immediately above. In requiring consistency, true beliefs and
appropriate desires, it appears to require maximizing agreement
between interpreter and interpreted, and thus a maximal conception of
what is constitutive of minds. The weaker interpretation instead
requires merely minimizing inexplicable error on the part of the
creature being interpreted, thus allowing for significant deviations
from psychological assignments that might be required by the stronger
interpretation. On this view, the interpreter puts himself into the
shoes of the interpreted, acknowledging evidential and cognitive
limitations that might prevent her from achieving maximal rationality
(Grandy 1973). As we will see in this section, how one interprets the
notion of rationality as constitutive directly affects how the
argument for mental anomalism is interpreted to work.

While Davidson never offers any substantive account of what the
proper source of evidence is for the physical, he often invokes the
notion of rationality as constraining mental ascription, and it is
clear that whatever constrains physical ascription is supposed to pull
in a different and potentially conflicting direction. One suggestive
way of getting at Davidson's idea here is through the traditional
distinction between ‘normative’ and
‘descriptive’ concepts. When we look to uncover
generalizations in the physically described world, what we find to
follow from a certain set of physical conditions is a brute
fact; our world is constituted in certain ways (in its governing
laws) that we could imagine to be different. We may come to an
empirical investigation with certain theoretical commitments that
inevitably lead us to read the data in some ways rather than others;
and there may indeed, as Davidson himself suggests, be constitutive
a priori principles that govern very basic physical concepts
such as ‘object’ and ‘event’ (Davidson 1970,
220; 1974b, 239; 1973a, 254; see 3.2 above). However,
the constraints are far looser and allow for a wide variation in terms
of empirical content—of what physical events and states can
follow from others. This is contrasted with mental ascription,
where the normative notion of rationality rules out the possibility of
certain mental states following from others. This line of thinking is
suggestive, but it is in need of considerable tightening.

Jaegwon Kim's account of Davidson's position (Kim 1985) attempts to do
just this. Kim argues that if there were strict lawlike relations
between mental and physical predicates, the ‘brute
factness’ and contingency of the physical would
‘infect’ the mental. For instance, rationality
considerations will typically lead us to attribute a belief that q to
a person if we attribute a belief that p and also attribute a
belief that p entails q. According to Kim's account, beliefs involving
very basic logical, semantic or conceptual relations like this hold of
necessity—we cannot make sense of possible worlds where beliefs
of the first two kinds are attributed but not the third.

Now, this may appear to be too strong a claim, in light of Davidson's
rejection of strict, purely psychological laws—mental anomalism
rejects the possibility of any strict laws in which mental predicates
figure, but Kim here appears to be deploying laws of the form
‘M1 & M2 → M3’. Kim
would reply that Davidson is only interested in rejecting strict
descriptive (i.e., explanatory, predictive) laws, not strict normative
laws (see below).

If physical predicates stood in strict lawful relations to mental
predicates, this contingency would ‘infect’ the mental in
the following sense. Suppose that there were strict bridge laws
correlating the instantiation of mental and physical properties,
‘P1 ↔ M1’
and
‘P2 ↔ M2’. Then,
Kim argues, rational principles of the form
‘M1 →
M2’ would enable the logical derivation of
physical laws like
‘P1 → P2’. Indeed,
the reverse would be true as well; starting with the physical law
‘P1 → P2’,
and assuming the psychophysical bridge laws, one could derive the
rational principle
‘M1 → M2’. However,
the metaphysical status of the rational principle and the physical law
are importantly different—rational principles are necessary,
true in all possible worlds, while physical laws, being contingent,
are not. In particular, with the bridge laws in place, a contingent
physical law could explain (through derivation) the rational
principle, undermining its status as necessary. Since it is the bridge
laws that enable these troublemaking derivations, they—and thus
strict psychophysical laws—are to be rejected. This is how Kim
makes sense of Davidson's suggestive claim that mental anomalism is
grounded in the fact that mental and physical explanation owe their
allegiance to different sources of evidence. (For related discussion,
see the supplement on
Explanatory Epiphenomenalism.)

Kim's argument rests upon two central assumptions. First, it assumes
that no distinction between strict and ceteris paribus laws
need play any role in reconstructions of Davidson's argument. It is,
purportedly, not the scope of a psychological law which
accounts for an asymmetry with physical laws, but rather the
point of each type of law (Kim 1985, 381). Second, it assumes
that there is a firm distinction between descriptive laws and
relations, on the one hand, and normative laws and relations, on the
other, that can bear the weight of mental anomalism (Kim 1985, 383) The
first assumption is clearly mistaken; as already noted, Davidson
heavily emphasizes the focus on strict laws in his own discussions of
Anomalous Monism, and explicitly allows for the possibility of hedged
laws incorporating mental predicates. Kim's reductio strategy,
then, would fail to uniquely identify the culprit responsible for
producing the trouble as the bridge laws rather than the rational
principle, all of which are strict. And while Davidson does
emphasize the normative status of mental predicates, he also
recognizes, as we have already noted (3.2
and 4.2), a normative
component to the physical realm, in constitutive a priori
principles. There does not appear to be a significant distinction
between descriptive and normative principles in Davidson's framework
that can bear the burden of mental anomalism, as required on Kim's
interpretation. (For further discussion of Kim's
interpretative strategy, see the supplement on
Kim's Reductio Strategy for Establishing Mental Anomalism.)

John McDowell also focuses on the normative nature of rationality, but
emphasizes a very strong conception of rationality as an ideal
constitutive of the mental, taking in more than merely the familiar
deductive relations—logical, semantic or
conceptual—deployed in Kim's reading (McDowell 1985,
391–4). McDowell appears to be guided by some of Davidson's
broader formulations and discussions of the principle of charity
(4.2), which extend to more general principles
governing action and belief formation, highlighted in Davidson's
discussions of irrationality (see Davidson 1982). For example, the
principle of continence requires one to act on the basis of all
available considerations, and the principle of total evidence requires
one to believe the hypothesis supported by all of one's evidence. And
the broad formulations entail that our conception of rationality
includes conceptions of the Good, and so the formation of rationally
appropriate desires, thus extending beyond constraints on belief and
action. According to McDowell, those inclined to think that mere
deductive relations can be captured in physical terms (see Loar 1981)
will find mental anomalism much more difficult to deny when taking
into account this stronger conception of rationality.

This stronger conception of rationality puts McDowell in a position
to exploit a crucial gap between rational norms and actual
explanations of behavior:

Finding an action or propositional
attitude intelligible, after initial difficulty, may not only involve
managing to articulate for oneself some hitherto merely implicit aspect
of one's conception of rationality, but actually involve becoming
convinced that one's conception of rationality needed correcting, so as
to make room for this novel way of being intelligible. (McDowell
1985, 392)

Just as our beliefs about empirical matters can be mistaken
in any given case, and we can make genuine discoveries about empirical
reality, just so with rationality. Clearly this claim is much
more plausible with the stronger conception of rationality that
McDowell is urging than the weaker conception limited to mere deductive
relations. McDowell goes on to argue that because of this
feature, we must be open to the possible reinterpretation of a person's
behavior and psychological states in light of our changing conception
of rationality, and how it changes cannot be anticipated in advance so
that rationality could be captured in a permanent set of principles
from which strict laws could be fashioned. For this reason, rationality
is uncodifiable. According to McDowell, this is what underlies
mental anomalism.

One might understand the reasoning here in the following way:
because it is built into our conception of rationality that our own
particular grasp of rationality may be mistaken on any given occasion
and is also inherently limited, no statement of psychological or
psychophysical generalizations could exhaust, and therefore explain,
our conception of rationality. If the concept of rationality
does not simply consist in one's conception, at any given
time, of rationality, then it cannot be captured in terms of the
actual goings on in one's brain (the same point applies if we
substitute “everyone's” for
“one's”). Therefore, strict lawlike relations between
the mental and the physical are impossible. This contrasts
interestingly with Kim's strategy: on McDowell's reading, it is partly
because no detailed statement of a rational principle could be
claimed to be necessarily true that there can be no psychophysical
laws.

A number of questions arise in considering McDowell's argument. It
appears to be heavily influenced by Davidson's remarks about the
ongoing nature of interpretation (Davidson 1970,
223; see 4.2). However, Davidson appeals to the
fact that new evidence—in the form of behavior and
environmental context—is always coming in that can force us to
revise existing interpretations of an agent. There is no mention of
shifting standards, or unarticulated or inarticulable
conceptions of rationality. Indeed, the implication is that
a stable standard, when taking into account new evidence, can
lead to revised interpretations of prior behavior. So McDowell appears
to be going beyond Davidson's own views about the concept of
rationality. Indeed, the idea that one is not able to fully articulate
a concept in the way suggested by McDowell—that it is in
effect ineffable –does not clearly sit comfortably with
Davidson's views about conceptual relativism and rejection of the idea
of untranslatable languages (see further the supplement on
Related Issues
(Anomalous Monism and Scheme-Content Dualism).

Further, and more importantly, McDowell's distinctive
uncodifiability claim, which rests on this view of rationality, looks
to be too general to underwrite a specific thesis like mental
anomalism. This becomes apparent when one asks why the very same
features that he is insisting are true of our conception of rationality
aren't also true of the key concepts that figure in explanations of the
physical world. Surely our concepts of physical reality outstrip any
particular conception we have at any given time, and the possibility of
mistaken application is built into them. And scientists are in the same
position as interpreters in terms of the possibility of new evidence
and its bearing on how previous evidence was understood. So far this
looks to be nothing more than a combination of a completely general
point about concepts together with the familiar problem of induction,
which plagues all empirical enquiry. McDowell's assertion that
“someone who aims at explanations of the ideal-involving kind
must be alive to the thought that there is sure to be a gap between
actual current conception and ideal structure in his own case as well
as others” (McDowell 1985, 392) doesn't appear to uniquely pick
out any particular explanatory framework. It therefore cannot tell us
anything distinctive about the metaphysical status of psychology.

If, however, the emphasis here falls on constitutive
principles in particular—as surely it must—then two
other problems arise. First, McDowell's reasoning doesn't tell us what
exactly it is about such principles that makes them resistant to
reduction, since, as we've just seen, that reasoning has failed to
distinguish them from empirical concepts in the physical sciences. And
second, as noted in 4.2, Davidson holds that there are constitutive
a priori principles underlying the physical sciences which
play a similar role there that rationality plays in psychological
explanation. So we are still in need of an explanation of why
psychology and physics cannot stand in strict lawlike relations. Now,
we did note there that such physical constitutive principles are far
more lenient than rationality, allowing for a greater variety of
empirical content—of what can follow from what. This indeed
accounts for an important asymmetry between mental and physical
explanation. And McDowell heavily emphasizes this point in his
discussion: that it is not merely a brute fact that rationality marks
the limits of intelligibility, while physical explanations do bottom
out in brute facts (McDowell 1985, 394). However, this point appears to
be entirely separable from the distinctive feature of McDowell's
reading of the argument for mental anomalism—it has nothing
especially to do with the idea of rationality as uncodifiable
in McDowell's specific sense. In fact, it is the key point behind Kim's
strategy, and it appears to have no essential connection to McDowell's
stronger views about rationality. One can think of rationality as
constitutive, as normative and as asymmetrical to the physical in the
way just noted—as Kim does—without buying into
McDowell's distinctive picture of it. So it looks like the salvageable
part of McDowell's actual argument for mental anomalism ultimately
reduces to Kim's. Uncodifiability appears to be a red herring.

Therefore, despite McDowell's extremely subtle and interesting views
about the nature of the ideal of rationality, in the end those views do
not appear to provide a secure foundation for mental anomalism. It is
only what is shared in common with Kim's strategy—the modal
asymmetry between rational and physical explanation—that bears
directly on mental anomalism. And that leaves McDowell's reading facing
the sorts of concerns raised in 4.2.1.

As we have seen above, Kim thinks that mental anomalism is
susceptible of a kind of proof. This seems to be something stronger
than Davidson himself claims (Davidson 1970, 215). In light of
Davidson's modesty about provability, and lack of explicit
argumentation, some commentators (Child 1992; see also McDowell 1979)
have suggested that mere reflection on the kinds of generalizations
that we draw upon in coming to understand each other supports (but
cannot prove) mental anomalism. Such generalizations are rules of thumb
that hold only for the most part, and require, for their application to
a given case, detailed contextual supplementation that cannot, by its
nature, be included in anything like a universal generalization. The
suggestion is that the sheer amount of contextual detail that would
need to be accounted for in any statement with even a hope of being
true is inappropriate for inclusion in strict lawful statements. A
related strategy is to point to a lack of fixed, predetermined ends
that all humans (or even any particular human over the course of her
life) aim for in situations of choice, or values to maximize when
deciding what to believe (such as simplicity, scope, and consistency in
the case of theory choice) (Child 1992). The thought here is that if
there are no such fixed ends or values, then no psychological
generalization could be complete—since in particular contexts
such ends or values play a crucial explanatory role in determining what
to do or believe.

It would seem, however, that reflection on the level of detail
required for strict laws in the physical sciences fails to provide for
an interesting asymmetry here. If one considers the number of factors
that would have to be taken in to account in order to state conditions
that guarantee that when a match is struck it will produce a flame, the
resulting strict law would be quite complex, and in a way not obviously
different from any putative strict laws in which mental predicates
figure, with contextual features included. And if there are indeed no
fixed ends or values in the realm of choice and a decision, this can be
accommodated in the same way—the contextual ends or values
could themselves be included in the putative strict laws. This would
complicate and expand the set of such laws, but as already noted this
is not something that would set mental generalizations apart from
physical ones. (For further discussion of rationality and the argument
for Anomalous Monism see Yalowitz 1997 and Latham 1999.)

We have been looking at different ways of making sense of and
justifying Davidson's claim that mental anomalism stems from the
constitutive role of rationality in mental ascription. In Davidson's
writings, however, another line of argument often surfaces which
focuses less on the rational nature of mental events and more on their
causal nature. As we have already seen, in his earliest work on action
Davidson argued that reasons explain actions by causing them, and he
later came to emphasize that what makes mental states and events what
they are is determined in part by their causes and effects. Particular
psychological explanations are causal (they invoke
causes—Davidson 1963), and are formulated in terms of causally
defined concepts (for propositional attitudes, see Davidson 1987b, 41;
for mental contents, see Davidson 1987a, 44). In later work he
frequently notes the anomic nature of causal concepts and causal
explanations, and how mental properties and reasons explanations are
anomic because of this—“reason-explanations…are in
some sense low-grade; they explain less than the best explanations in
the hard sciences because of their heavy dependence on causal
propensities” (Davidson 1987b, 42; see also Davidson 1991, 162).
If mental concepts are causally defined, and strict laws do not employ
causally defined concepts, then mental anomalism appears to follow
straight away, without need of any detour through issues concerning
the rationality of mental concepts.

Extending this reasoning, Davidson writes that

[m]ental concepts…appeal to causality because they are
designed, like the concept of causality itself, to single out from the
totality of circumstances which conspire to cause a given event just
those factors that satisfy some particular explanatory interest.
(Davidson 1991, 163)

This appears to ground the causal definition of anomic properties
(whether mental or otherwise) in the fact that they answer to
particular explanatory interests. This is contrasted with the case of
‘ultimate physical’ properties: “Explanation in terms
of the ultimate physics, though it answers to various interests, is not
interest relative” (Davidson 1987b, 45). This seems to collapse
the distinction between psychology and all the other special sciences
with respect to the question of anomalism. All of the latter answer to
particular explanatory interests, and are thus selective with
respect to the total sufficient condition for an effect-type (see
Davidson 1987b, 45); the causal definition, and thus anomalism, of
their vocabularies is owed to this interest-relativity and selectivity.
‘Ultimate physics’, on the other hand, “treats
everything without exception as a cause of an event if it lies within
physical reach (falls within the light cone leading to the
effect)” (Davidson 1987b, 45).

Davidson repeats these sorts of claims about the anomic nature of
causally defined properties in a number of places in later writings,
but at no point does he clearly bring them into contact with his early
remarks concerning the constitutive role of rationality in
psychological ascription. And he never provides argument in support of
this general thesis concerning causality. It is natural to wonder why,
given this general thesis about causally defined concepts, rationality
should be thought to underwrite mental anomalism. And it becomes
imperative to know why that general thesis is plausible (for
discussion, see Yalowitz 1998a).

With regard to the first issue, there is some evidence that Davidson
is confusing two distinct questions: why mental concepts cannot stand
in lawlike relation to physical concepts, and why mental concepts
cannot be eliminated in favor of physical concepts in the explanation
of human behavior. Given the general thesis about casually defined
properties, we have an understanding of why mental concepts are
anomic. But this leaves open the question whether we ought to
continue to traffic in anomic concepts generally, and mental concepts
in particular. Why not eliminate them in favor of the nomic physical
concepts? Here, the rationality of mental concepts may be thought to
provide an answer. If we wish to understand why an agent performed the
action that she did, as opposed to having a full sufficient causal
explanation of why her body moved as it did, we are interested in a
selective explanation—that part of the total sufficient
condition that satisfies the particular explanatory interests behind
reasons-explanations (Davidson 1991, 163). Those interests highlight
the normative nature of reason and action—their responsiveness
to the principle of charity and ideal of rationality. Rationality, on
this line of thinking, does not account for mental anomalism; but it
does speak to the question of mental realism
(see further 6.2). (For further
discussion of the anomic nature of causally defined concepts and its
bearing on Anomalous Monism, see Yalowitz 1998a. For more on the
relation between rational explanation and mental realism, see the
supplement on
Explanatory Epiphenomenalism. For discussion
of issues closely related to the casual definition argument, see 6.3
and the supplement on
Related Issues
(Mental Anomalism and Semantic Externalism).

So far we have looked at Davidson's three premises in support of
Anomalous Monism—the interaction, cause-law and anomalism
principles. In this section, we examine the conclusion that Davidson
draws on the basis of these principles—the token-identity
theory of mental events, according to which every causally interacting
mental event is token-identical to some physical event. We will look at
the derivation and nature of this theory, some questions about its
adequacy, as well as the additional thesis that mental properties
supervene on physical properties. As we shall see, both the
token-identity and supervenience claims turn out to be controversial,
in their motivation as well as in their consistency with mental
anomalism. One key point to keep in mind at this point is that monism
is supposed to be derived from the principles and other assumptions
that, taken individually, could be acceptable to positions opposing
monism.

To begin with, it is worth pointing out that Davidson is concerned
only with the ontological status of events, and not substances.
Descartes, for instance, argued for the claim that mind and body are
distinct entities. While Descartes' position has implications for
accounts of mental events, the issues concerning event and substance
identity are distinct (see Latham 2001). Davidson clearly takes himself
to be establishing something that is inconsistent with Cartesian
dualism, however, and it is useful briefly to look at how Anomalous
Monism bears upon substance dualism.

According to Descartes, mind and body are distinct substances in
part because they do not share essential properties in common. In
particular, minds do not occupy a spatial location, while bodies
necessarily do. Since mental events thus constitute changes occurring
in a nonspatially-located entity, they also do not occupy a spatial
region. Bodily events, on the other hand, do occupy spatial locations
by virtue of being changes in material substances, which themselves are
spatially located. On Descartes' view, then, particular mental and
physical events cannot be token-identical, since they fail to share a
crucial property in common without which identity is unintelligible.
While Anomalous Monism is not officially concerned with the ontological
status of substances, it thus appears to have consequences that are
inconsistent with Descartes' substance dualism—though it
doesn't by itself establish substance monism, it does rule out the
Cartesian thought that mental and physical events fail to be identical,
and so conflicts with one of the bases for Cartesian substance
dualism.

The structure of Davidson's derivation of the token-identity of
causally interacting mental events with physical events appears to be
straightforward: causally interacting mental events (the interaction
principle) must instantiate some strict law property (the cause-law
principle) but mental properties are not suitable for inclusion in
strict laws (the anomalism principle). So mental events must
instantiate some other property, which is suitable for such inclusion.
Given Davidson's invocation of the causal closure of the physical
domain, according to which every physical event has a physical
explanation, he moves rather quickly to the conclusion that this other
property must be physical, since closure entails that physical
properties have a privileged status, which suggests that they hold out
the promise of strict laws. (Davidson also has a tendency simply to
identify as ‘physical’ those properties that figure in
strict laws (Davidson 1970, 224; 1995a, 266), but this would of
course beg the question of mental anomalism.) Consequently, causally
interacting mental events must be token-identical with physical events,
ruling out Cartesian as well as other forms of dualism.

There are serious problems with the assumption of causal closure of
the physical in Davidson's framework (for discussion, see the
supplement on
Causal Closure of the Physical in the Argument for Anomalous Monism). It is difficult, however, to see how Davidson
can move from the claim that mental events must instantiate
non-mental, strict law properties to the claim that these properties
must be physical without assuming closure. Why assume that only
‘physical’ properties are nomic? This raises interesting
issues about the nomic status of other special sciences—the
relevant ones here being biology and chemistry—but there do not
appear to be explicit, conclusive resources in Davidson's own thinking
for addressing this. Yalowitz 1998a has, however, provided an
interpretation of Anomalous Monism stressing Davidson's views on
causality and the nomic status of dispositions
(see 4.3) in which causal closure
is derivedfrom the cause-law principle,
token-identity and the anomalism of causally defined properties. On
this interpretation, the strict law properties that mental events must
instantiate turn out to be physical because only physical properties
are non-causally individuated—all special science properties are
causally individuated, and all such properties are anomic.

Davidson's token-identity theory is dramatically different than
previous identity theories of mind, in both it's a priori
status as well as its stance towards the role of laws in justifying
monism. Previous theories had argued that claims concerning the
identity of particular mental and physical events depended upon the
discovery of lawlike relations between mental and physical properties.
These theories thus held that empirical evidence supporting such laws
was required for particular identity claims. According to Anomalous
Monism, however, it is precisely because there can be no such
strict laws that causally interacting mental events must be
identical to some physical event. The token-identity thesis thus
requires no empirical evidence and depends on there being no
lawlike relations. It in effect justifies the token-identity of mental
and physical events through arguing for the impossibility of
type-identities between mental and physical properties or kinds
(Davidson 1970, 209, 212–13; see Johnston 1985).

An important point to recognize in Davidson's version of
token-identity is that he is not simply deriving the conclusion that
mental events bear some property that we would intuitively acknowledge
as ‘physical’ (such as spatial location). As pointed out in
2.1, the relevant ‘physical’
properties would more likely have to resemble the sorts of properties
currently invoked in physics, our most mature science and the one
closest to issuing in strict laws. This point has generated numerous
objections to Davidson's token-identity theory, but it also has been
overlooked by some objectors (see below). Davidson's central claim is
that what makes a mental event identical to a physical event is that
the mental event has a physical description. In Davidson's original
formulation, monism entailed that every mental event can
be uniquely singled out using only physical concepts (1970,
215). It is this position that became the target of some Davidson's
critics (5.2). However, Davidson eventually
came to explicitly deny that his monism commits him to the possibility
of providing descriptions of mental events or actions in physical
terms suitable for strict laws (Davidson 1999d, 639; 1999b,
653–4). He noted that strict laws will say something to the
effect that “whenever there is a certain distribution of forces
and matter in a field of a certain size at time t, it will be
followed by a certain distribution of forces and matter in a field of
a certain size at time t′” (Davidson 1999d,
639). And he claimed that both the antecedents and consequents of such
laws, when covering particular mental events and actions, will cover
much larger regions of space than merely the agent or her action. Why?
Because while singular causal statements are singular, and
therefore select from a complete set of causal factors those that are
salient or in line with our particular explanatory interests, strict
laws don't themselves select—“that's what makes them
strict” (Davidson 1999d, 640; see Yalowitz 1998a for an extended
discussion of this issue and its bearing on the argument for both
mental anomalism as well as monism). Davidson soft-pedals how this
view bears on the uniqueness claim in the official statement of
Anomalous Monism, parsing away that claim in favor of the blander idea
that “some physical description applies to each mental
event” (Davidson 1999b, 654). As subtle as it seems, this
appears to be a fundamental shift in Davidson's thinking about monism,
though it goes unexplored in his later work and has failed to attract
the attention of his critics.

In any case, Anomalous Monism thus does not inherit the problem of
how to justify specific identifications between mental and physical
events, because the claim that there is a physical description for each
mental event is established purely a priori. And the physical
descriptions are not (indeed, cannot be) specifiable in precise and
uniquely identifying spatial and temporal terms. As we are about to see
(5.2), each of these points is overlooked by many of Davidson's
critics. That the latter is overlooked is understandable, given its
late appearance. However, the former point has always been fundamental,
and critics' failure to appreciate it is curious.

Davidson additionally claims that the relation between the mental
and physical properties is not merely haphazard or coincidental. A
relationship of supervenience obtains between the two (Davidson 1970,
214; 1973a, 253; 1993; 1995a, 266). (Davidson
never argues for supervenience. For discussion, see the
supplement on
Supervenience and the Explanatory Primacy of the Physical.)
A working statement of this relationship is that if two events
fail to share a mental property, they will fail to share at least one
physical property (Davidson 1995a, 266)—or, equivalently, if two
events share all of their physical properties, they will share all of
their mental properties. It is meant to articulate a kind of dependency
of the mental on the physical, and correlatively a kind of explanatory
primacy to the physical, but without claiming any kind of reductive
relation between the mental and the physical. The working statement's
truth depends, it seems, on the thought that the distribution of
physical properties somehow explains the distribution of
mental properties—failure to share a mental property
depends upon/is explained by failure to share at least one
physical property. The supervenience relation is usually understood to
issue in generalizations of the following kind:
‘P1 → M1’,
‘P2 → M1’, etc.
(where antecedent and consequent occur at
the same time). This allows for the empirical possibility that a number
of different physical state kinds underlie the same mental state kind
(for more on this, see the supplement on
Related Issues
(Mental Anomalism and Semantic Externalism)).
However, it also
appears to suggest the existence of lawlike relations between physical
and mental properties, and so to be in tension with mental anomalism.
This issue will be explored in 5.3.

The token-identity thesis has been the subject of a number of
interesting criticisms. Many of them, however, are difficult to bring
fully into contact with Davidson's own particular version of the
thesis, primarily because Davidson's version is derived a
priori from the other premises in his framework. So, for instance,
it has been argued that mental events do not bear the burden of the
spatiotemporal precision of physical events that they would need to if
the former were genuinely identical to the latter (Hornsby 1981; Leder
1985). For example, it would seem arbitrary to identify the deduction
of some conclusion from a chain of reasoning with some particular
neural event or set of neural events occurring at a specific time and
place in the brain—especially given the micro-precision of the
neural framework. Compare attempting to provide physical description
for the action of paying back a debt—how does one determine the
spatial and temporal parameters with the precision demanded by the
language of physics? Distinguishing between “the” physical
event, as opposed to its causes and its effects, can seem daunting if
not outright nonsensical (Leder 1985; see also di Pinedo 2006).
Further, it has been argued that the only possible empirical evidence
for specific token-identity claims could be type-identities between
either those or other mental and physical properties, because evidence
needs to be drawn from variant cases in order to sort out merely
coincident from identical events (Leder 1985).

Such criticisms become difficult to evaluate given Davidson's a
priori procedure for establishing the token-identity thesis. He
can respond that we already know, a priori, that any
particular mental event must instantiate some physical property if it
causally interacts with any mental or physical event, given the
cause-law and anomalism principles. Questions about how this physical
property, whatever it is, relates to properties currently invoked in
neuroscience come later and are necessarily secondary to this monistic
conclusion. And there is no guarantee (indeed, it is quite unlikely)
that neuroscientific properties currently in vogue are candidates for
strict-law properties. As we have just seen (5.1), Davidson eventually
came to explicitly associate the physical properties that cover mental
events with broad descriptions covering large space-time regions.
Further, it would confuse epistemology with metaphysics to insist that,
because we can only establish which physical property some mental token
event instantiates by leaning on some type-correlations between other
mental and physical properties, token-identity claims presuppose
type-identity. How we discover the particular physical properties is
one thing; whether there can be psychophysical laws is quite another,
and not settled by the method of discovery.

We also need to keep in mind that Davidson embraces the possibility
of substantive mental-physical correlations (ceteris paribus
psychophysical laws), which directly address these epistemological
issues. More generally, Davidson's token-identity claim is that the
predicates that come to form the vocabulary of the as-yet unknown
strict-law science will be capable of being used to describe mental
events. While we cannot judge this claim by appealing to features of
current neuroscience, it also seems that it should be possible to
adjudicate conceivability concerns. And, putting aside Davidson's later
views, while we are not currently in the business of assigning
fine-grained spatiotemporal parameters to mental events, it does not
seem obvious that we couldn't come to accept such assignments on the
basis of theoretical considerations without thereby committing
ourselves to the existence of type-identities. However, Davidson's
official position, early and late, has always been that we do not need
to be capable of making such assignments in order to assert
token-identity—there must simply be such true assignments, and
this is something we know on the basis of a purely a priori
argument. (Davidson 1999b; for further discussion of this issue, see
the supplement on
Related Views (Bare Materialism);
for a different criticism of token-identity,
see the supplement on
Related Views (Other Positions).
For a criticism based upon Davidson's own treatment of
causal explanation, see Horgan and Tye 1985. For discussion of the
criticism that Davidson's monism is too weak to warrant the label
‘materialism’, see the supplement on
Token-Identity and Minimal Materialism).

We have seen that Davidson supplements his monism with a claim of
supervenience. There are many different conceptions of the
supervenience relation (see Kim 1993b), and Davidson ultimately came to
identify his version with what is called “weak”
supervenience, in contrast to “strong” and
“global” supervenience. Briefly, the basic differences
between these positions are as follows. Weak supervenience links
specific mental and physical properties within but not across possible
worlds, while strong supervenience links those properties across
worlds. Global supervenience links the class of mental properties as a
whole with the class of physical properties as a whole within but not
across worlds, but does not constrain relations between specific pairs
of mental and physical properties. Weak supervenience comes down
to the view that mental properties depend upon those physical
properties they are correlated with within a particular possible world,
but those very same physical properties may, in another possible world,
correlate with very different (or even no) mental properties. Weak
supervenience is thus stronger than global supervenience, in that it
posits correlations between particular pairs of mental and physical
properties, but weaker than strong supervenience in that it recognizes
the possibility that these correlations can fail to obtain in other
possible worlds. (It should be noted that Davidson never brought his
views on supervenience into contact with his later views, noted above,
about the broad nature of the physical properties that mental events
must instantiate according to Anomalous Monism. It is not at all clear
whether or how these views can be combined. In the following discussion
of supervenience, this complication will be ignored, and it will be
assumed that the physical properties in question are not of this broad
nature, since this is how Davidson's own discussions of supervenience
seem to proceed, and certainly what his critics presuppose.)

The puzzling aspect of Davidson's doctrine of supervenience arises
independently of fine points of the disagreement between the competing
conceptions of supervenience sketched above. Whether the dependency is
between particular mental and physical properties, or sets of the two,
and whether or not the dependency holds only within or also across
possible worlds, it appears that it entails that there will exist
strict laws on the basis of which mental events can be predicted and
explained that were supposed to be ruled out by the anomalism
principle. Davidson sometimes claims (Davidson 1995a, 266) that
supervenience is actually entailed by Anomalous Monism, in
which case it would appear to follow that Anomalous Monism itself is an
inconsistent theory—entailing both that there cannot be any
strict psychophysical laws (the anomalism principle) and that there
must be such laws (supervenience). But generally his position appears
to be that Anomalous Monism is simply consistent with supervenience
(Davidson 1993, 7). If supervenience and Anomalous Monism are indeed
inconsistent, and the former is rejected, the question of the
plausibility of a materialist position with no discernible relation
between mental and physical properties arises (see the
supplement on
Supervenience and the Explanatory Primacy of the Physical).
(The caveat about the relation between Davidson's later views about
physical descriptions and supervenience noted at the end
of 5.1. should be kept in mind here.)

Why does supervenience appear to generate strict laws? When Davidson
first stated the supervenience claim, he articulated it in the
following terms: “there cannot be two events alike in all
physical respects but differing in some mental respects”
(Davidson 1970, 214)). This formulation appears to entail strict
psychophysical laws of the form ‘P1 →
M1’. Davidson later came to focus on the inversion of
this formulation: “if two events fail to share a mental property,
they will fail to share at least one physical property” (Davidson
1995a, 266). The advantage of this reformulation is that it brings out
the fact that the requisite physical differences need not be the
same in each case of mental difference (see Davidson 1973a, 253–4).
As Davidson says,

although supervenience entails that any change in a mental
property p of a particular event e will be
accompanied by a change in the physical properties of e, it
does not entail that a change in p in other events will be
accompanied by an identical change in the physical properties of those
other events. Only the latter entailment would conflict with
[Anomalous Monism]. (Davidson 1993, 7)

There seem to be two problems here, however. First, the inverted
reformulation actually entails the original thesis—that if two
events share all physical properties they will share all mental
properties—and so once again generates strict psychophysical
laws. Second, even if the accompanied physical changes can be
different, that simply generates more strict psychophysical
laws—‘ P1 → M1’,
‘P2 → M1’,
and so on. So it is hard to see why Davidson thinks that the second
formulation is consistent with the anomalism principle.

Some defenders of Davidson (Child 1992, 224; see also Davidson 1973,
258) have responded to the apparent tension between supervenience and
mental anomalism by emphasizing that the degree of detail that would
have to go into the formulation of such laws would make them useless
for prediction, since it is unlikely that the relevant initial
conditions will repeat. But as we have seen
(4.2.3), this seems to be true of any
candidate for a strict law—it must take into account all
possible interfering conditions, and doing so becomes quite unwieldy
for generating predictions. And in any case, such laws would still
provide strict explanations of mental events, contrary to
Davidson's own formulation of mental anomalism. So the problem that
supervenience ‘laws’ seem to pose for the anomalism
principle remains.

Other defenders of Davidson (see Macdonalds 1986) have responded to
this problem by arguing that the existence of strict supervenience laws
is compatible with mental anomalism so long as we are not actually able
to state any such laws and thus be in a position to use them to predict
and explain actual mental events—which is certainly the case
currently and likely for the foreseeable future. This suggestion
exploits a literal reading of Davidson's official statement of the
anomalism principle, which denies the possibility of strict laws on the
basis of which mental events can be explained or predicted.
But in doing so, it makes Anomalous Monism into a much weaker position,
dependent on the cognitive limitations of human beings. It in effect
becomes a contingent epistemological position rather than the necessary
metaphysical doctrine it purports to be.

Davidson in one place offers a very different suggestion in response
to the problem. He claims that the supervenient relations between
mental and physical predicates that he envisages are of a ceteris
paribus nature. He accepts the requirement that any satisfactory
account of the relation between mental and physical properties must
permit appeal to local correlations and dependencies between specific
mental and physical properties (Davidson 1993, 9). But he blocks any
entailment from this requirement to strict psychophysical laws,
suggesting that such ‘correlations’ and
‘dependencies’ are of a ceteris paribus form.

Such a ceteris paribus conception of supervenience has not
been discussed in the extensive literature on the topic (its
possibility is recognized and endorsed by Kim 1995, 136; however, see
Kim 1993, 24–25) and it is unclear whether it can deliver a suitably
strong notion of dependency to satisfy materialist intuitions. But it
does seem to be an attractive way of reconciling supervenience with
mental anomalism so that Anomalous Monism remains a consistent
theory.

It has been widely held that Anomalous Monism cannot avoid
epiphenomenalism—the view that mental events lack
causal/explanatory powers. At a first approximation, the concern
derives from a tension between mental anomalism and the apparently
privileged status assigned to physical properties in Davidson's
framework—in particular, that all events are physical, and all
physical events have a strict explanation in terms of other physical
events. It then becomes an important question what sort of
causal/explanatory role mental properties can play when all events
already have a physical explanation.

Some welcome this result, holding that mental events explain actions
in a sui generis way not accountable for in the terms of
typical scientific explanations (see von Wright 1971; Stoutland 1976;
Wilson 1985; Ginet 1995; Campbell 1998 and 2005 and related discussion
in the supplement on
Explanatory Epiphenomenalism). Many,
however, see this charge as devastating to the prospects of Anomalous
Monism's attempt to occupy a position between reductionist materialism
and dualism. Without a distinctive causal role for mental events to
play in the explanation of action, many think that they would lack the
sort of robust reality needed to compete with reductionism and dualism.
On this way of thinking, only causal powers can justify mental realism.
So if Anomalous Monism cannot avoid epiphenomenalism, it appears to
open the door to eliminativist materialism, which holds that mental
vocabulary and explanations are vacuous and ought to be thrown out and
replaced by neuroscience (assuming, which seems extremely doubtful,
that neuroscience can itself supply strict laws—if not, then
this line of thought would lead to throwing out all but
‘physical’ strict law properties and explanations).

As noted, the epiphenomenalist worry arises from two points that are
absolutely basic to Anomalous Monism—first, that mental events
are at the same time physical events, and, second, that while mental
predicates cannot figure into strict causal laws, physical predicates
must. Early critics moved quickly from these points to the
epiphenomenalist conclusion that mental properties are causally
irrelevant, because there are always strict law
properties—physical properties—to causally explain the
occurrence of an event. (For detailed discussion of this line of
argument, see the supplement on
Mental Properties and Causal Relevance.)
Among many other problems with this line of argument, however, there
is the one immediately capitalized on by Davidson: that within the
extensionalist metaphysical framework in which Anomalous Monism is
developed (2.1 above), properties don't cause
anything, and so can be neither causally relevant nor
irrelevant. According the Davidson, only events are
causal relata. He expresses general skepticism about
epiphenomenalist objections to Anomalous Monism that depend on the
idea that events cause ‘by virtue’ of the properties they
instantiate (Davidson 1993, 6, 13). This is closely connected to his
sharp distinction between causation—a metaphysical relation
between particular events independently of how they are
described—and explanation—which relates events only as
they are described in particular ways. But as we will now see, this
doesn't end the concerns about epiphenomenalism.

Critics of this extensionalist line of defense insisted that related
questions remained about Anomalous Monism even taking into account the
distinction between causation and explanation. In
particular, they questioned whether mental properties could play
any genuine explanatory role—whether they had explanatory
relevance—given the priority assigned to physical
properties in Davidson's framework. Why think that mental
properties explain anything given that the events which instantiate
them always also instantiate physical properties that figure in causal
laws? One thought here is that genuine explanations require laws,
and mental anomalism, in ruling out psychological and psychophysical
laws, cannot account for any explanatory role for mental properties vis
a vis physical or mental events.

In response, Davidson notes that while Anomalous Monism rejects the
possibility of strict laws in which mental predicates can figure, it
allows for ceteris paribus psychological and psychophysical
laws (Davidson 1993, 9–12). His point appears to be that if backing by
law is sufficient for explanatory relevance, then mental properties are
explanatorily relevant. (Davidson and his critics often slide between
the issues of causal and explanatory relevance, but the latter issue is
clearly what is at stake given Davidson's views about causal
efficacy and properties.) Second, Davidson appeals to the
supervenience of mental properties on physical properties in order to
ground the explanatory role of mental properties. Davidson says that

properties are causally efficacious if they make a difference to
what individual events cause, and supervenience ensures that
mental properties do make a difference to what mental events
cause. (Davidson 1993, 15)

The first point does not get developed by Davidson in any systematic
way, though it has been explored by others interested in
defending nonreductive monism from epiphenomenalist concerns. Some have
focused on exploiting ceteris paribus covering laws for
psychophysical casual relations, claiming that this allows mental
properties to be sufficient for their effects, thus providing the
needed type of explanatory role (McLaughlin 1989; Fodor 1989, 1991).
Others have attempted to sidestep the issue of covering laws entirely
by appealing directly to the truth of psychological and psychophysical
counterfactuals in grounding the explanatory role of mental properties
(LePore and Loewer 1987, 1989; Horgan 1989). Davidson himself
instead focused on supervenience (although as we are about to see, the
possibility of ceteris paribus laws enters into his
account).

Supervenience implies that

if two events differ in their
psychological properties, they differ in their physical properties
(which we assume to be casually efficacious). If supervenience holds,
psychological properties make a difference to the causal relations of
an event, for they matter to the physical properties, and the physical
properties matter to causal relations. (Davidson 1993, 14)

The
point here is not simply that mental properties inherit or piggyback on
the causal powers of the physical properties on which they supervene.
Rather, Davidson appears to be claiming that mental properties
influence the causal powers of their subvenient physical
properties.

One problem with Davidson's response here is its reversal of the
dependency relationship between mental and physical properties
typically claimed in supervenience relationships. A central
rationale for positing supervenience is to mark a kind of explanatory
primacy to the subvenient properties (see the supplement on
Supervenience and the Explanatory Primacy of the Physical).
And this is reflected in the first part of Davidson's formulation
above—surely a difference in psychological properties entails
(requires) a difference in physical properties because the
difference in physical properties is needed in order to
explain the difference in psychological properties. So the sense
in which psychological properties ‘matter’ to physical
properties is that changing the former amounts to a change in the
latter because a change in the latter explains a change in
the former. This does not appear to be helpful in establishing the
explanatory relevance of mental properties. Another problem, discussed
above (5.3), is that it is difficult to
see how a supervenience relation of sufficient power to make mental
properties explanatory of an event's physical properties in the way
Davidson seems to suggest does not issue in strict laws. So it is
unclear how supervenience is consistent with the anomalism principle,
and thus how it can help block epiphenomenalist concerns, although we
did previously note one potentially worthwhile but unexplored
possibility—a ceteris paribus supervenience
relation—which Davidson endorses.

Kim has explored a related but different route from Anomalous Monism
to mental epiphenomenalism—the problem of explanatory exclusion
(Kim 1989, 44). A causal explanation of an event cites a sufficient
condition for that event's occurrence. This seems to exclude the
possibility of other independent causes or explanations of that event.
So if, as Anomalous Monism entails, physics can provide a sufficient
explanation of any particular event, there appears to be no room for
an independent and irreducible mental explanation of an event
(Davidson 1993, 15). It is because the cause instantiated some
particular physical property that the effect (which happens to
instantiate a mental property) came about. Any mental properties that
the cause instantiates seem superfluous in explaining why the effect
occurred—unless those properties are identical or related in
some strict lawlike way to the physical properties, something ruled
out by the anomalism principle.

Davidson responds by arguing that citing only the physical
properties of the cause to provide a sufficient explanation of an
action does not address the particular interests that psychological
explanations of actions serve—providing the reasons of the
agent in light of which she performed the action that she did. Serving
these explanatory interests compensates for the fact that such
explanations cannot be sharpened into strict laws or folded neatly into
physical laws (Davidson 1991, 163). We only understand why the agent
waved her hand—why the effect is of the mental kind
‘waving one's hand’ (as opposed to merely ‘one's hand
going up and down’)—by citing mental properties
of the causing event, such as her wanting to greet her friend. The
citation of physical properties of the causing event and the associated
mere bodily movement will not bring about such understanding, assuming
mental anomalism, because of the lack of any reductive relationship
between either the physical properties of the cause and the
agent's reasons or the physical properties of the effect and the
agent's action.

Here we see the interest-relativity of explanation and its bearing
on explanatory relevance (see the supplement on
Mental Properties and Causal Relevance) playing an important role for Davidson. Mental
properties must be cited if we want a rational explanation of
mental effects. Davidson's response to epiphenomenalist
concerns can thus be described as a kind of ‘dual
explananda’ theory of the explanatory role of mental
properties. According to this theory, for every (causally interacting)
mental event there are two distinct explananda in need of explanation:
an event of a certain physical type and an event of a certain mental
type. Mental properties are accorded an ineliminable and (given
Anomalous Monism) irreducible explanatory role by virtue of their
singular capacity to make intelligible the occurrence of other mental
properties through the sui generis relation of
rationalization. This reflects the point made at the end of
4.3 by the
causal definition interpretation of the argument for mental anomalism:
that rationality underlies, not mental anomalism, but rather mental
realism. (For related discussion of the dual explananda
approach, see Macdonalds 1995 and Gibbons 2006.)

It should be noted, however, that it is not the case that
only mental properties can explain and be explained by the occurrence of
mental properties. That would lead to an “outlet” problem,
with mental properties being explanatorily insulated from physical
properties—something inconsistent with the way in which we
ordinarily think of mental-physical interaction. A blow to the head can, for
instance, explain the occurrence of a thought. And a thought can
explain the movement of an object, as when my decision to quench my
thirst leads to the movement of a glass of water to my lips. However,
the blow cannot rationalize the thought, and the decision cannot
rationalize the movement of the glass (though it can rationalize the
action of moving the glass). Davidson's dual explananda strategy provides no account of such phenomena (for discussion of the
outlet problem, see Gibbons 2006). Nonetheless, so long as there are occurrences of mental
properties in need of the distinctive kind of explanation provided by
rationalization, mental properties occupy an ineliminable explanatory
role. And given Anomalous Monism, that role is irreducible. It is worth
noting that this dual explananda strategy is consistent with
Davidson's commitment to the causal closure of the physical
domain (Crane 1995 seems to miss this point)—every
physical event can have a physical explanation, even if the mental
component of some physical events can be rationally explained only
through appeal to mental components of the causing event. Therefore,
however causal closure ultimately enters into Anomalous Monism (see the
supplement on
Causal Closure of the Physical and Anomalous Monism),
it does not appear to create any further problems for
Anomalous Monism's ability to account for the ineliminable, irreducible
explanatory role of mental properties.

The interest-relativity of causal explanation is thus crucial in
Davidson's grounding of the ineliminable explanatory role of
mental properties within the framework of Anomalous Monism. If, as
Anomalous Monism contends, mental event-types such as actions are not
reducible to physical-event types, then the only way to explain actions
(as opposed to mere bodily movements) so as to make them
intelligible is by appeal to the mental properties of the
cause—reasons. (For discussion of whether, in light of this,
reason explanations can still be maintained to be causal
explanations within the framework of Anomalous Monism, see the
supplement on
Explanatory Epiphenomenalism.)

A final point to consider in evaluating the epiphenomenalist
objections to Anomalous Monism is the way in which causality enters
into the constitution of reasons and reasons-explanations according to
Davidson. Before we have established the anomalism principle, or go on
to derive monism, we already know that reasons explain actions by
causing them (the ‘because’ problem discussed
in 2.2). And, as we have seen
(4.3), we know that propositional attitudes
and mental contents are individuated, and thus defined, partially in
terms of what they are caused by and cause (for attitudes, see
Davidson 1987b, 41; for contents, see Davidson 1987a, 444, and
extended discussion in the supplement on
Related Issues
(Mental Anomalism and Semantic Externalism)).
But if something cannot even be recognized as a
reason unless it is a cause, then the charge that mental properties are
causally impotent appears to have difficulty getting any traction. And
since these claims are prior to the argument for monism, they are
neutral about whatever else reasons must be in order to be causes. So
reasons must be recognized as causes prior to any discovery that they
are also physical events. This appears to secure the causal potency of
reasons in a way entirely independent of the claim of token-identity. Within Davidson's framework, reasons can only play the
rationalizing and explanatory role that they do by virtue of their
causal nature.

Many of Anomalous Monism's epiphenomenalist critics do not address
this rich causal background. As we have seen, the background is not
sufficient by itself to silence all epiphenomenalist concerns. But it
does significantly affect how those concerns can be formulated and addressed.
Anomalous Monism is clearly deeply committed, at a number of levels,
to the causal explanatory relevance of the mental, and so charity
suggests that we try to understood it in a way such that these
commitments are respected. The dual explananda strategy
discussed above (6.2) provides one
promising framework for doing this, while at the same time displaying
sensitivity to the sorts of concerns driving the epiphenomenalist
objections.

Despite the initial appearance of simplicity in its assumptions,
structure and argumentation, we have turned up several important
problems and lacunae that stand in the way of any overall final
assessment of the plausibility of Anomalous Monism. While the central
objections it has faced have derived from epiphenomenalist concerns,
the force of these objections is not clear. Arguably, the most serious
difficulties for Anomalous Monism are not with its adequacy but with
its justification. We still stand in need of a clear argument for how
rationality leads to the anomalism principle; there are the substantial
problems surrounding the status of the causal closure of the physical
and its bearing on monism; and the cause-law principle's strictness
requirement is still in need of a compelling rationale. Even with these
problems, Anomalous Monism continues to provide an extremely useful
framework for exploring fundamental issues and problems in the
philosophy of mind, and has earned a central place on the rather short
list of important positions on the relation between mental and physical
events and properties.

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